The present invention relates to a method of producing a pelletized fuel from garbage, sludge or any other waste materials.
More particularly, the invention relates to a method of producing briquettes from house garbage or waste sludge by means of enriching the waste organic products with organic materials of a high constant heat value, for example coal and under application of pressures to the products.
Methods of making briquettes or pellets from waste products have been known in the art. One of such methods is described, for example in U.S. Pat. No. 3,910,775. This patent discloses a method and apparatus for processing organic waste products, such as refuse, sewage or the like to produce briquettes. In a continuous process the collected refuse is first freed from ferromagnetic articles, then shredded and conveyed, with the addition of acidic waste, into a rolling mill which dewaters and forms the refuse and waste mixture into briquettes. These briquettes can be either used as a fuel or used as a filtering material in the device for dewatering sewage sludge before they are finally burned out. Due to the pressure applied to the mixture of the refuse and waste in the rolling mill a partial sterilization of organic waste products with respective destruction of pathological germs can be obtained and briquettes which can be easily transported and stored can be produced. However, a complete sterilization of the waste products has not been yet possible with known conventional methods of making briquettes from waste products. In the method disclosed in the above mentioned patent the mixture of refuse with acidic waste is utilized for producing briquettes. This mixture of waste obtained from a coal processing is used mainly to produce briquettes which can serve as a filtering material for separating phosphates from the sludge in a sludge processing.
One of the known methods of the foregoing type is also disclosed in the FR-A-994 789. The French publication describes a method of producing briquettes from organic waste products by compressing a mixture of waste products under pressures of about 800 bar where a partial melting of the products takes place to avoid an addition of a special binder. However, in this conventional method a satisfactorily high heat value and complete sterilization of the final product are not achieved. Thus, the method disclosed in the French publication as well as other known prior art publications do not suggest means which could lead to the production of commercially available briquettes made out of waste and suitable as solid fuel for heating houses and industrial buildings.